Micro Dan amps

I've recently installed a new Micro Dan 1875kv.
Man this think screams (speed and torque) much more than what it replaced (1300kv). The out going motor was only pushing 12oz of thrust with a 7x6 prop. (not really a 1300kv motor?) and a 3c lipo
The micro Dan only offers an additional 575kv, yet it's producing a whopping 31oz of thrust on the same battery using a 7x5 prop. According to Go brushless (micro Dan) it's continuous Amp with the prop is 26 Amp. But they say (via email) they always add 10% (+2.6 amps) to the Amp ratings for obvious reasons.

​​​​​​My question is in the prop. Is there such a huge difference in amps used between 7x5 and 7x6 props? Seems to me that it would barely be worth mentioning.

Kv is not a rating, not a figure of merit.
Achieving a higher Kv is no big deal, just a matter of lowering number of winds.
Higher rpm for given voltage is supposed to happen: rpm_noload = voltage × Kv.

It's all about what the motor wants to do versus what the motor can do.
Kv, expressed in rpm/volt, matches desired rpm and voltage, nothing more. It says nothing about a motors max. power and max.current.

So, changes in setup (and lousy Kv specifications!) can have surprisingly considerable/huge effects.
E.g. doubling voltage will four(2²)fold current, doubling Kv will eight(2³)fold current, and doubling prop diameter will sixteen(2⁴)fold current.
Even a small 10% change/difference in Kv will already lead to a 30% difference in current.

Pick a preferred cell count (voltage) and pack capacity for how to deliver the power.

Pick a prop that will a) fit on the model and b) fly the model how you want - often as big as will fit is a good choice, but if high speed is the goal, a smaller diameter higher pitch prop will be more appropriate.

Look for a size class of motors that will handle the peak power - a very conservative guide is to allow 1 gram motor weight for every 3 watts peak power.

Then, look for a motor in that weight range that has the Kv to achieve the power desired with the props you can use - a calculator such as eCalc allows very quick trial and error zooming in on a decent choice. For a desired power and prop, you'd need higher Kv if using a 3 cell pack compared to a 4 cell pack. Or for a desired power and cell count, you'd need higher Kv if driving a smaller diameter high speed prop compared to a larger prop for a slow model.

The reason I suggest picking Kv last, is that prop choices have bounds - the diameter that will physically fit and the minimum size that can absorb the power you want. On the other hand, combinations of voltage and Kv are much less constrained - at least before you purchase the components.

So Kv is not a figure of merit, in that higher or lower is better, it is simply a motor characteristic that you exploit to make your power system do what you want, within the constraints you have, e.g. limited prop diameter, if it's a pusher configuration, or if you already have a bunch of 3S packs and don't want to buy more, and so on.